Coupling of Amino Carboranes to Carboxylic Acid Containing Substrates

Synthesis of Closo-1,7-Carboranyl Alkyl Amines

Of the three closo-carborane isomers (C(2)B(10)H(12)), closo-1,2-carborane has been used most widely in the synthesis of carboranyl amines. However, closo-1,2-carboranes are prone to deboronation to nido-7,8-carborane under various conditions including attack by basic amino groups. In order to overcome this problem, closo-1,7-carboranyl ethyl-, propyl-, and butylamine were synthesized, which should be more stable towards basic deboronation than their closo-1,2-carboranyl counterparts. These closo-1,7-carboranyl amines (5, 18 and 19) were synthesized using two different methods, both starting from the corresponding closo-1,7-carboranyl alkyl iodides (3, 14 and 15). One of the carboranyl alkyl amine (5) was conjugated with folic acid to form a closo-1,7-carborane-folic acid bioconjugate (20).

Synthesis of Gd(III)-C-palmitamidomethyl-C'-DOTAMA-C(6)-o-carborane: a new dual agent for innovative MRI/BNCT applications

C-(2-Benzyloxy)-ethyl-C'-N-tert-butoxycarbonyl-aminomethyl-o-carborane (8), a potentially useful intermediate for BNCT, has been synthesised. This intermediate can be readily functionalised with several biological vectors and MRI contrast agents. In this work intermediate 8 has been functionalised with a palmityl chain for lipophilic targeting and with Gd(III)-DOTAMA-C(6)-NH(2) as MRI detector. This combination yielded Gd(III)-C-palmitamidomethyl-C'-DOTAMA-C(6)-o-carborane (14) as a dual MRI-BNCT agent.